Depends how fast your internet connection is.......

Kind of my point.

I know nothing about mobile broadband speeds, so what would one expect from such a device? Everything I find on the web at the moment is concentrating on the download speed, and the technical specs only tell what the device is capable of in perfect circumstances.

In a real world example such as Paul noted, if I'd been snapping away with my camera, which had been offloading copies to the mifi doodad, which was then sending them into cyberspace, how many 15MB RAW files would it have done by the time security collared me and demanded I delete the images?

What you really need is a wifi device in the card (I think these already exist), a device that accepts the wireless then saves to a low power large capacity storage (such as an SSD or laptop hard drive) then deletes them from the memory card when done, and a bit of hacking for them to all work. That way even in an area with no net access (I think the wifi cards atm use wireless networks in places like mcdonalds) you safely remove the images to a secure location

Sounds like a fun project actually